Tetrachlor-indigo and process of making same.



' No Drawing.

4.5-dichlor-indoxyl carboxylic UNITED STATES PATENT rare.

PAUL JULIUS, VIKTOR VILLIGER, AND PAUL NAVVIASKY, OF LUDWIGSHAFEN-ON-THE- RHINE, GERMANY, ASSIGNORS TO .BADISOHE ANILIN & SODA FABRIK, 0 LUDWIGS- HAFEN-ON-THE-RHINE, GERMANY, A CORPORATION.

rErRAcHLoR-rnnmo Ann rnocnss or MAKING saME.

955,410. Specification of Letters Patent.

Application filed November 17, 1909.

Patented Apr. 19, rare. Serial no. 528,562..

To all whom it mag concern;

Be it known that We, PAUL J ULIUs, Ph. 1)., VIKTOR VILLIGER, Ph. 1)., and PAUL Nawr'l ASKY, Ph. D.,' chemists, the first and third subjects of the Emperor of Austria-Hun-v gary and the second a citizen of the Swiss ltepublic are 1 a u w b hai'en-on-the-Rhine, Germany, have invented new and-useful Improvements in Tetrachlor-Indigo and Processes of Making Same, of which the following is a specification.

Our invention relates to the production of 4.4.5.5-tetrachlor-indigo. Vi e have invented a process for its production by the saponi It can be converted into the corresponding fication and oxidation of an ester of 4.5- I indigo coloring matter by boiling tw.0 hunchlor-indoxyl carboxylic acid. Thus, upon dred and-sixty parts of it with'six thousand. operating in this way upon the methyl ester parts of water of l.5-dichlorindoxyl carboxylic acid, we, parts of caustic potash, obtain the new product 4.45.5tetrachlorj While passing a current indigo of a constitution corresponding-to the the solution.

Introduce, While stirring, two hundred and ninety-two parts of the methyl ester of 3.4-dichlorphenyl-glycin --2 carboxylic acid into a solution of twenty-three parts of so dium in one thousand parts of methyl alcohol, and maintain the Whole at seventy der s centigrade for thirty minutes. Distil off the meth 1 alcohol, digest the residue with one thdu sa arts of water and two hundred parts of thir per cent. acetic acid, and filter off and wash and dry the 4.5- dichlor-indoxylcarboxylic acid ester, which is insoluble in water and is difiicultly soluble in most of the common organic solvents.

for thirty minutes, of coal gas through Then add twelve thousand f l parts of boiling water to the mixture and /\/NH\ NH\ lpass air through it, at a temperature'oit v I about one hundred degrees cen tigrade, until l l l the oxldatlon is complete. It desired, the I saponification can be carried out in the ab sence of coal gas.

Now what we claim is z- -l. The process of producing erastetrachlor-indigo by saponii'ying and oxidizing an ester of 4.5-dichlor indoxyl carboxylic acid substantially as described.

2. Asa new article of manufacture 4.4.5.5-tetrachlor indigo which when dry of a greenish blue powder, yielils a blue solution in cold concentrated sulfuric acid, and a blue solution in hot dimethyl anilin; it dyes co.l:on particularly greenish It consists, when dry, of a greenish blue powder which yields a blue solution in cold l concentrated sulfuric acid and a blue solul tion in hot dimethyl anilin. It differs from all known tetrachlor-indigoes in that it dyes cotton from a vat exceptionally greenish shades of blue which are fast against wash ing, light, and chlorin. Moreover, the said shades retain their greenish tint when viewed by artificial light, whereas the other tetrahalogcn indigoes hitherto describcdassume a reddish or violet-black tint under similar conditions. Upon being oxidized in aqueous suspension with nitric acid, our 4i.4'-5.i-tetrachlor-indigo yields 4.5-dichlorisatin which can be recrystallized from glacial acetic acid and thus obtained in the form of red needles which melt at about 247 C.

The following example will serve to illustrate further the nature of this invention and how it can be carried into practical effect, but our invention is not confined to this example. The parts are by Weight. In this example we first, for convenience, describe the production of the methyl ester of acid.

suspension by means of nitric acid gives rise to 4.5-dichlor-isatin, which aij-vdichlor-isatin can be recrystallized from glacial acetic acid and thus be obtained in the form of red needles whichmelt at about 247 C. v

In testimony whereofflwe have hereunto set our hands in the presence of two sul scribing Witnesses.

PAUL JULIUS. VIKTOR VILLIGER. PAUL NAWIASKY.

Witnesses:

J. ALEc. LLOYD, W. W. Sonmmr.

consists and five hundred and eleven shades of blue, ahd on oxidation in aqueous 

